Semitic writing systems such as that used to write Arabic are unique among st alphabetic writing systems in that in Semitic systems short vowels are represented as diacritics on consonant letters, and not represented at Allin text intended for skilled readers. Arabic is unique here in that the letter used to represent a consonant differs in shape as a function of the position of that letter in the letter sequence. These features of written Arabic make the study of learning to read in this language of particular interest. We studied the acquisition of Arabic reading in children in Grades 3, 4 and 6, and also tested adult readers Our results indicated (a) despite the orthographic differences between the Arabic and English writing systems learning to read Arabic, like learning to read English, is characterized by the existence of an initial "discrimination-net" phase, followed by aphonological-recoding phase, after which there is a gradual transition to an orthographic phase and (b) that children do not acquire fluency in the position-specific properties of the script until rather late during the course of reading acquisition, though skilled reader shave this knowledge so deeply en-grained that it is difficult for them to process written text consisting of letters that represent the right phonemes in the right positions but which are written in forms inappropriate for their positions in the orthographic sequence.